Measuring Crr is technically difficult, so one should always keep an
critical mind when judging Crr measurement results. The results gathered on
this page have all been measured on different surfaces with different
methods, so the results are not necesseraly directly comparable. The
results have mostly been gathered in one place to give some pointers
about the relative rolling resistance merits of different tires and not
to claim absolute values for Crr.
Here is a link
to some recent measurements of Crr.